This research seminar provides an overview of public international law and applies the current legal framework to various cyber incidents in order to categorize them. It introduces a basic understanding of public international law, different types of international law violations, as well as permissible response options. The seminar pairs this introduction with an in-depth study of various cyber incidents that will enable students to effectively identify criteria to categorize cyber incidents as well as identify areas of contestation. Questions will include, among others: Can a cyber incident justify a state using its right to self-defense? What about a cyber incident that does not rise to the level of an ‘armed attack’ or ‘use of force’? What are permissible response options for a targeted state? What is the international legal status of espionage activities in cyberspace?